title: Biosynthesis of tropomyosin and troponin during development of the chicken skeletal muscle.
abstract: The level of functional mRNA coding for myofibrillar proteins was studied during development of the chicken skeletal muscle. RNA isolated from the developing chicken muscle directed protein synthesis in a wheat germ cell-free system. By means of polyacrylamide gel electrophoresis and immunological analysis, tropomyosin subunits and troponin components were identified among the cell-free translation products. The mRNA activities for alpha- and beta-subunit of tropomyosin were prominent in the embryonic breast muscle as well as in the embryonic leg muscle. At the early post-embryonic stage, the mRNA activity for beta-subunit disappeared from the breast muscle, while those for alpha- and beta-subunit were detectable in the leg muscle. Troponin-C and troponin-I synthesized in vitro in response to the muscle RNA formed a binary complex in the presence of calcium ion. Despite the observed difference in molecular weight between troponin-Ts in the breast and leg muscle, RNA preparations from the two muscles encoded identical troponin-Ts whose molecular weights were indistinguishable from that of troponin-T present in the breast muscle of adult chicken. It is suggested from these results that the biosynthesis of tropomyosin is regulated at the pre-translational level during the development of the chicken skeletal muscle, whereas post-translational (or co-translational) events may produce the tissue-specific form of troponin-T.
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D002474:Cell-Free System; D002645:Chickens / Q000254:growth & development*; D004591:Electrophoresis, Polyacrylamide Gel; D005779:Immunodiffusion; D024510:Muscle Development; D009124:Muscle Proteins / Q000096:biosynthesis*; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000378:metabolism; D014335:Tropomyosin / Q000096:biosynthesis*; D014336:Troponin / Q000096:biosynthesis*
chemical_list: D009124:Muscle Proteins; D012333:RNA, Messenger; D014335:Tropomyosin; D014336:Troponin; D002118:Calcium